.TH PCREGREP 1
.SH NAME
pcregrep - a grep with Perl-compatible regular expressions.
.SH SYNOPSIS
.B pcregrep [options] [long options] [pattern] [file1 file2 ...]
.
.SH DESCRIPTION
.rs
.sp
\fBpcregrep\fP searches files for character patterns, in the same way as other
grep commands do, but it uses the PCRE regular expression library to support
patterns that are compatible with the regular expressions of Perl 5. See
.\" HREF
\fBpcrepattern\fP
.\"
for a full description of syntax and semantics of the regular expressions that
PCRE supports.
.P
A pattern must be specified on the command line unless the \fB-f\fP option is
used (see below).
.P
If no files are specified, \fBpcregrep\fP reads the standard input. The
standard input can also be referenced by a name consisting of a single hyphen.
For example:
.sp
  pcregrep some-pattern /file1 - /file3
.sp
By default, each line that matches the pattern is copied to the standard
output, and if there is more than one file, the file name is printed before
each line of output. However, there are options that can change how
\fBpcregrep\fP behaves. In particular, the \fB-M\fP option makes it possible to
search for patterns that span line boundaries.
.P
Patterns are limited to 8K or BUFSIZ characters, whichever is the greater.
BUFSIZ is defined in \fB<stdio.h>\fP.
.
.SH OPTIONS
.rs
.TP 10
\fB--\fP
This terminate the list of options. It is useful if the next item on the
command line starts with a hyphen, but is not an option.
.TP
\fB-A\fP \fInumber\fP
Print \fInumber\fP lines of context after each matching line. If file names
and/or line numbers are being printed, a hyphen separator is used instead of a
colon for the context lines. A line containing "--" is printed between each
group of lines, unless they are in fact contiguous in the input file. The value
of \fInumber\fP is expected to be relatively small. However, \fBpcregrep\fP
guarantees to have up to 8K of following text available for context printing.
.TP
\fB-B\fP \fInumber\fP
Print \fInumber\fP lines of context before each matching line. If file names
and/or line numbers are being printed, a hyphen separator is used instead of a
colon for the context lines. A line containing "--" is printed between each
group of lines, unless they are in fact contiguous in the input file. The value
of \fInumber\fP is expected to be relatively small. However, \fBpcregrep\fP
guarantees to have up to 8K of preceding text available for context printing.
.TP
\fB-C\fP \fInumber\fP
Print \fInumber\fP lines of context both before and after each matching line.
This is equivalent to setting both \fB-A\fP and \fB-B\fP to the same value.
.TP
\fB-c\fP
Do not print individual lines; instead just print a count of the number of
lines that would otherwise have been printed. If several files are given, a
count is printed for each of them.
.TP
\fB--exclude\fP=\fIpattern\fP
When \fBpcregrep\fP is searching the files in a directory as a consequence of
the \fB-r\fP (recursive search) option, any files whose names match the pattern
are excluded. The pattern is a PCRE regular expression. If a file name matches
both \fB--include\fP and \fB--exclude\fP, it is excluded. There is no short
form for this option.
.TP
\fB-f\fP\fIfilename\fP
Read a number of patterns from the file, one per line, and match all of them
against each line of input. A line is output if any of the patterns match it.
When \fB-f\fP is used, no pattern is taken from the command line; all arguments
are treated as file names. There is a maximum of 100 patterns. Trailing white
space is removed, and blank lines are ignored. An empty file contains no
patterns and therefore matches nothing.
.TP
\fB-h\fP
Suppress printing of filenames when searching multiple files.
.TP
\fB-i\fP
Ignore upper/lower case distinctions during comparisons.
.TP
\fB--include\fP=\fIpattern\fP
When \fBpcregrep\fP is searching the files in a directory as a consequence of
the \fB-r\fP (recursive search) option, only files whose names match the
pattern are included. The pattern is a PCRE regular expression. If a file name
matches both \fB--include\fP and \fB--exclude\fP, it is excluded. There is no
short form for this option.
.TP
\fB-L\fP
Instead of printing lines from the files, just print the names of the files
that do not contain any lines that would have been printed. Each file name is
printed once, on a separate line.
.TP
\fB-l\fP
Instead of printing lines from the files, just print the names of the files
containing lines that would have been printed. Each file name is printed
once, on a separate line.
.TP
\fB--label\fP=\fIname\fP
This option supplies a name to be used for the standard input when file names
are being printed. If not supplied, "(standard input)" is used. There is no
short form for this option.
.TP
\fB-M\fP
Allow patterns to match more than one line. When this option is given, patterns
may usefully contain literal newline characters and internal occurrences of ^
and $ characters. The output for any one match may consist of more than one
line. When this option is set, the PCRE library is called in "multiline" mode.
There is a limit to the number of lines that can be matched, imposed by the way
that \fBpcregrep\fP buffers the input file as it scans it. However,
\fBpcregrep\fP ensures that at least 8K characters or the rest of the document
(whichever is the shorter) are available for forward matching, and similarly
the previous 8K characters (or all the previous characters, if fewer than 8K)
are guaranteed to be available for lookbehind assertions.
.TP
\fB-n\fP
Precede each line by its line number in the file.
.TP
\fB-q\fP
Work quietly, that is, display nothing except error messages.
The exit status indicates whether or not any matches were found.
.TP
\fB-r\fP
If any given path is a directory, recursively scan the files it contains,
taking note of any \fB--include\fP and \fB--exclude\fP settings. Without
\fB-r\fP a directory is scanned as a normal file.
.TP
\fB-s\fP
Suppress error messages about non-existent or unreadable files. Such files are
quietly skipped. However, the return code is still 2, even if matches were
found in other files.
.TP
\fB-u\fP
Operate in UTF-8 mode. This option is available only if PCRE has been compiled
with UTF-8 support. Both the pattern and each subject line must be valid
strings of UTF-8 characters.
.TP
\fB-V\fP
Write the version numbers of \fBpcregrep\fP and the PCRE library that is being
used to the standard error stream.
.TP
\fB-v\fP
Invert the sense of the match, so that lines which do \fInot\fP match the
pattern are the ones that are found.
.TP
\fB-w\fP
Force the pattern to match only whole words. This is equivalent to having \eb
at the start and end of the pattern.
.TP
\fB-x\fP
Force the pattern to be anchored (it must start matching at the beginning of
the line) and in addition, require it to match the entire line. This is
equivalent to having ^ and $ characters at the start and end of each
alternative branch in the regular expression.
.
.SH "LONG OPTIONS"
.rs
.sp
Long forms of all the options are available, as in GNU grep. They are shown in
the following table:
.sp
  -A   --after-context
  -B   --before-context
  -C   --context
  -c   --count
       --exclude (no short form)
  -f   --file
  -h   --no-filename
       --help (no short form)
  -i   --ignore-case
       --include (no short form)
  -L   --files-without-match
  -l   --files-with-matches
       --label (no short form)
  -n   --line-number
  -r   --recursive
  -q   --quiet
  -s   --no-messages
  -u   --utf-8
  -V   --version
  -v   --invert-match
  -x   --line-regex
  -x   --line-regexp
.
.SH "OPTIONS WITH DATA"
.rs
.sp
There are four different ways in which an option with data can be specified.
If a short form option is used, the data may follow immediately, or in the next
command line item. For example:
.sp
  -f/some/file
  -f /some/file
.sp
If a long form option is used, the data may appear in the same command line
item, separated by an = character, or it may appear in the next command line
item. For example:
.sp
  --file=/some/file
  --file /some/file
.sp
.
.SH DIAGNOSTICS
.rs
.sp
Exit status is 0 if any matches were found, 1 if no matches were found, and 2
for syntax errors and non-existent or inacessible files (even if matches were
found in other files). Using the \fB-s\fP option to suppress error messages
about inaccessble files does not affect the return code.
.
.
.SH AUTHOR
.rs
.sp
Philip Hazel
.br
University Computing Service
.br
Cambridge CB2 3QG, England.
.P
.in 0
Last updated: 16 May 2005
.br
Copyright (c) 1997-2005 University of Cambridge.
